The MoCA 2.0 standard defines Modulation Profiles that have a set of parameters that determines the transmission between nodes, including preamble type, cyclic prefix length, modulations per subcarrier and transmit power. Each MoCA 2.0 Node maintains two PHY profiles for each 100 MHz unicast link: one for Nominal Packet Error Rate of 1e-6 (NPER) and one for Very Low Packet Error Rate of 1e-8 (VLPER). Similarly, two PHY profiles are maintained for 100 MHz Greatest Common Density (GCD) or Broadcast profiles: one for NPER (1e-6) and one for VLPER (1e-8). The GCD is a modulation format computed by a node for transmission to multiple recipient nodes. For the GCD or Broadcast format, the modulation used for each subcarrier is chosen to be the greatest possible modulation density that is less than or equal to the modulation density for that subcarrier as reported in the most recent Error Vector Magnitude (EVM) Probe Report the node sent to each of the other nodes. The EVM probe is used to determine the optimum modulation scheme for a set of subcarriers. During a new Node admission procedure, PHY profiles for both NPER and VLPER are distributed. Since the VLPER packets are more robust to errors than the NPER packets, the modulations per subcarrier of the VLPER profile are usually equal or lower than the corresponding modulations per subcarrier of the NPER profile.
However, the above-mentioned modulation schemes require a large amount of memory for each subcarrier. More specifically, 1,920 bits per modulation profile. Assuming 15 nodes, the total memory required for storing NPER and VLPER modulation profiles is 57,600 bits.
Accordingly, an apparatus and method to reduce modulation profile memory size may be desirable.